Some conventional filter cigarettes have a CO/Tar delivery ratio (each measured in mg per cigarette) of a little less than unity, though this ratio is more usually unity or greater. Tar is herein defined as Particulate Matter, Water- and Nicotine-free (PMWNF). It is very desirable to reduce CO delivery, but prior measures aimed at achieving this have resulted in unsatisfying taste delivery and/or in unsatisfactory draw performance, and/or have involved expensive filter structures.